Abstract:

To enhance the mixing performance of the impinging stream reactor, a novel self-excited oscillating impinging jet reactor was designed, and the flow characteristics and mixing performance within this reactor were numerically simulated. The shear stress transport k-‍ω (SST) turbulence model was adopted to simulate the fluid flow pattern within the nozzle and the flow pattern distribution within the impinging stream reactor. The influences of the Reynolds number on the oscillation frequency of the jet and the mixing performance of the reactor were investigated. The research results showed that the oscillation of the jet at the nozzle outlet was controlled by the repetitive growth process of the circulation bubble within the nozzle cavity, and the flow field distribution within the reactor was affected by the deflection angles of the two jets. The oscillation frequency of the jet increased with the increase of the Reynolds number. High-frequency oscillation accelerated the shear and radial movement velocities of the two fluids. When the Reynolds number was 30000 and the mixing time was 50s, the mixing intensity at the outlet reached 0.962. The smaller the difference in the deflection angles of the two jets on both sides of the impinging stream reactor, the faster the mixing speed. The research results enrich the theoretical understanding of the fluid oscillation characteristics of the impinging stream reactor and provide theoretical references for the development of new reactors.

Key words: impinging stream, oscillating jets, flow characteristics, mixing performance, numerical simulation

摘要：

为提高撞击流反应器的混合性能，设计了一种新型自激振荡撞击流反应器，并采用数值模拟方法对其内部流场动力学特征与物质混合过程进行了分析。采用剪切应力输运k-ω（SST）湍流模型模拟了喷嘴内流体流动模式及撞击流反应器内流型分布，考察了雷诺数对射流振荡频率及反应器混合性能的影响。研究结果表明：喷嘴出口射流的振荡是由喷嘴腔室内循环泡的重复生长过程控制，反应器内流场分布受两侧射流偏转角度影响。射流振荡频率随着雷诺数的增大而增加，高频振荡使得两股流体的剪切和径向运动速度加快，雷诺数为30000，混合时间为50s时，反应器出口混合强度达到0.962。本研究拓展了基于振荡射流的撞击流动力学理论体系，为高效反应器设计提供了新思路。

关键词: 撞击流, 振荡射流, 流动特性, 混合性能, 数值模拟